Evolving Cancer Survival in Taiwan Over 25 Years: Nowcasting with the Survivorship–Period–Cohort Model

Background: Cancer has been the leading cause of death in Taiwan since 1982, but long-term survival trends remain incompletely characterized. We evaluated 25-year cancer survival trends, including stage-specific outcomes. Methods: We analyzed Taiwan Cancer Registry data for patients aged 15–99 years diagnosed with cancer between 1996 and 2021. We estimated the cancer survival index for all sites combined and age- and sex-adjusted 5-year relative survival ratios for individual cancers. The Ederer II cohort method was used for diagnoses before 2018, and the survivorship-period-cohort model was used to nowcast survival for diagnoses in 2018–2020. TNM stage–specific survival was evaluated for 17 cancers diagnosed during 2010–2017. Results: The 5-year cancer survival index increased from 46.8% in 1996 to a nowcast estimate of 56.2% in 2020. Survival improved most for small intestine, lung, and nasopharyngeal cancers, with lung adenocarcinoma also shifting toward earlier-stage diagnosis. Survival declined for cervical, renal pelvis, bladder, brain and CNS, and gallbladder cancers. Stage-specific survival remained largely stable for most cancers, whereas lung cancer showed clear gains, including across all stages of adenocarcinoma and in late-stage squamous cell carcinoma. Conclusions: Nationwide cancer survival improved substantially, but persistent cancer-specific gaps highlight priorities for early detection, treatment, and cancer control. Impact: These population-based estimates provide timely evidence for monitoring cancer prognosis, evaluating cancer-control progress, and identifying cancers and stages requiring greater clinical and public health attention.